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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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How do human CO2 emissions compare to natural CO2 emissions?

What the science says...

Select a level... Basic Intermediate

The natural cycle adds and removes CO2 to keep a balance; humans add extra CO2 without removing any.

Climate Myth...

Human CO2 is a tiny % of CO2 emissions

“The oceans contain 37,400 billion tons (GT) of suspended carbon, land biomass has 2000-3000 GT. The atpmosphere contains 720 billion tons of CO2 and humans contribute only 6 GT additional load on this balance. The oceans, land and atpmosphere exchange CO2 continuously so the additional load by humans is incredibly small. A small shift in the balance between oceans and air would cause a CO2 much more severe rise than anything we could produce.” (Jeff Id)

At a glance

Have you heard of Earth's carbon cycle? Not everyone has, but it's one of the most important features of our planet. It involves the movement of carbon through life, the air, the oceans, soils and rocks. The carbon cycle is constant, eternal and everywhere. It's also a vital temperature control-mechanism.

There are two key components to the carbon cycle, a fast part and a slow part. The fast carbon cycle involves the seasonal movement of carbon through the air, life and shallow waters. A significant amount of carbon dioxide is exchanged between the atmosphere and oceans every year, but the fast carbon cycle's most important participants are plants. Many plants take in carbon dioxide for photosynthesis in the growing season then return the CO2 back to the atmosphere during the winter, when foliage dies and decays.

As a consequence of the role of plants, a very noticeable feature of the fast carbon cycle is that it causes carbon dioxide levels to fluctuate in a regular, seasonal pattern. It's like a heartbeat, the pulse of the Northern Hemisphere's growing season. That's where more of Earth's land surface is situated. In the Northern Hemisphere winter, many plants are either dead or dormant and carbon dioxide levels rise. The reverse happens in the spring and early summer when the growing season is at its height.

In this way, despite the vast amounts of carbon involved, a kind of seasonal balance is preserved. Those seasonal plant-based peaks and troughs and air-water exchanges cancel each other out. Well, that used to be the case. Due to that seasonal balance, annual changes in carbon dioxide levels form regular, symmetric wobbles on an upward slope. The upward slope represents our addition of carbon dioxide to the atmosphere through fossil fuel burning.

Fossil fuels are geological carbon reservoirs. As such, they are part of the slow carbon cycle. The slow carbon cycle takes place over geological time-scales so normally it's not noticeable on a day to day basis. In the slow carbon cycle, carbon is released by geological processes such as volcanism. It is also locked up long-term in reservoirs like the oceans, limestone, coal, oil or gas. For example, the "37,400 billion tons of 'suspended' carbon" referred to in the myth at the top of this page is in fact dissolved inorganic carbon in the deep oceans.

Globally, the mixing of the deep ocean waters and those nearer the surface is a slow business. It takes place over many thousands of years. As a consequence, 75% of all carbon attributable to the emissions of the industrial age remains in the upper 1,000 m of the oceans. It has not had time to mix yet.

Fluctuations in Earth's slow carbon cycle are the regulating mechanism of the greenhouse effect. The slow carbon cycle therefore acts as a planetary thermostat, a control-knob that regulates global temperatures over millions of years.

Now, imagine the following scenario. You come across an unfamiliar item of machinery that performs a vital role, for example life support in a hospital. It has a complicated control panel of knobs and dials. Do you think it is a good idea to start randomly turning the knobs this way and that, to see what happens? No. Yet that is precisely what we are doing by burning Earth's fossil fuel reserves. We are tinkering with the controls of Earth's slow carbon cycle, mostly without knowing what the knobs do - and that is despite over a century of science informing us precisely what will happen.

Please use this form to provide feedback about this new "At a glance" section. Read a more technical version below or dig deeper via the tabs above!


Further details

Before the industrial revolution, the CO2 content in the air remained quite steady for thousands of years. Natural CO2 is not static, however. It is generated by a range of natural processes, and absorbed by others. The carbon cycle is the cover-all term for these processes. It has both fast and slow components.

In the fast carbon cycle, natural land and ocean carbon remains roughly in balance and has done so for a long time. We know this because we can measure historic levels of CO2 in the atmosphere both directly, in ice cores and indirectly, through proxies. It's a seasonal response to things like plant growth and decay.

In stark contrast to the fast carbon cycle, the slow version operates over geological time-scales. It has affected carbon dioxide levels and therefore temperatures throughout Earth's history. The reason why the slow carbon cycle is so important is because many of the processes that lead to long-term changes in carbon dioxide levels are geological in nature. They take place over very long periods and do so on an erratic basis. The evolution of a species that has deliberately disturbed the slow carbon cycle is another such erratic event.

Annually, up to a few hundred million tonnes of carbon pass through the slow carbon cycle, due to natural processes such as volcanicity. That's small compared to the fast carbon cycle, through which some 600 billion tonnes of CO2 pass to-and-fro annually (fig. 1). However, remember that the fast carbon cycle is a give-and-take seasonal process. The slow carbon cycle instead runs in one direction or another over periods typically measured in millions of years.

Global carbon budget

Fig. 1: Schematic representation of the overall perturbation of the global carbon cycle caused by anthropogenic activities averaged globally for the decade 2012–2021. See legends for the corresponding arrows and units. The uncertainty in the atmospheric CO2 growth rate is very small (±0.02 GtC yr−1) and is neglected for the figure. The anthropogenic perturbation occurs on top of an active carbon cycle, with fluxes and stocks represented in the background. Adapted from Friedlingstein et al. 2022.

Through a series of chemical and geological processes, carbon typically takes millions of years to move between rocks, soil, ocean, and atmosphere in the slow carbon cycle. Because of these geological time-scales, however, the overall amount of carbon involved is colossal. Now consider what happens when more CO2 is released from the slow carbon cycle – by digging up, extracting and burning carbon from one of its long-term reservoirs, the fossil fuels. Although our emissions of 44.25 billion tons of CO2 (in 2019 - source: IPCC AR6 Working Group 3 Technical Summary 2022) is less than the 600 billion tons moving through the fast carbon cycle each year, it adds up because the land and ocean cannot absorb all of the extra emitted CO2: about 40% of it remains free.

Human CO2 emissions therefore upset the natural balance of the carbon cycle. Man-made CO2 in the atmosphere has increased by 50% since the pre-industrial era, creating an artificial forcing of global temperatures which is warming the planet. While fossil-fuel derived CO2 is a small component of the global carbon cycle, the extra CO2 is cumulative because natural carbon exchange cannot absorb all the additional CO2. As a consequence of those emissions, atmospheric CO2 has accumulated to its highest level in as much as 15 to 20 million years (Tripati et al. 2009). This is what happens when the slow carbon cycle gets disturbed.

This look at the slow carbon cycle is by necessity brief, but the key take-home is that we have deeply disturbed it through breaking into one of its important carbon reservoirs. We've additionally clobbered limestones for cement production, too. In doing these things, we have awoken a sleeping giant. What must be done to persuade us that it needs to be put back to sleep? 

Cartoon summary to counter the myth

Cherry picking

This Cranky Uncle cartoon depicts the "Cherry picking” fallacy for which the climate myth "Human CO2 emissions are small" is a prime example. It involves carefully selecting data that appear to confirm one position while ignoring other data that contradicts that position. Source: Cranky Uncle vs. Climate Change by John Cook. Please note that this cartoon is illustrative in nature and that the numbers shown are a few years old.

Last updated on 17 September 2023 by John Mason. View Archives

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Argument Feedback

Please use this form to let us know about suggested updates to this rebuttal.

Further reading

Real Climate goes in-depth into the science and history of C13/C12 measurements.

The World Resources Institute have posted a useful resource: the World GHG Emissions Flow Chart, a visual summary of what's contributing to manmade CO2 (eg - electricity, cars, planes, deforestation, etc).

UPDATE: Human CO2 emissions in 2008, from fossil fuel burning and cement production, was around 32 gigatoones of CO2 (UEA).

Denial101x video

Here is the relevant lecture-video from Denial101x - Making Sense of Climate Science Denial

Comments

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Comments 201 to 208 out of 208:

  1. (-Snip-) Their CO2 models strongly depend on the ocean surface temperature. Taking a (-snip-) feedback of temperature rise due to extra CO2, you can (-snip-) any "relaxation time", even millions of years. I find the Bern CO2 model much more transparent: http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0889.1996.t01-2-00006.x/pdf The only drawback of that model is that it discards the dynamics of biologic removal of CO2 from the ocean. It implicitely assume that it is "constant". Look at the pulse response in Fig.3 and you see that the relaxation time is 5 years or even less. As it has been numerously measured in 50-ies and 60-ies of the last century. And yes, I claim it is the problems with a too weak sink of CO2, not with extra emission. That is why CO2 is rising. Even if the oceans are a net CO2 sink now.
    Response:

    [DB] Allegations of fraud and impropriety on the part of the IPCC snipped.  It is time to familiarize yourself with the Comments Policy here.  Future comments containing such violations will be simply deleted.

    Thank you in advance for your understanding and your compliance in this matter.

  2. KR, IIRC the 74 year figure is the e-folding time, i.e. the time taken for the concentration to fall to 1/e of its initial value.
  3. bugai, your position appears to be self contradictory. Let's assume for the moment that your arguments of '5 year relaxation time' and 'CO2 accumulation due to pollution decreasing natural sinks' are correct... I don't see how that changes the conclusion that the increase in atmospheric CO2 levels is entirely due to human emissions. You concede that natural emissions are less than natural sinks... ergo natural emissions CANNOT be causing the rise in atmospheric CO2 levels. You also agree that humans are emitting enough to increase atmospheric levels by about 4ppm per year, but the actual rate of increase is only about 2ppm. You argue that this accumulation is due to reduced natural sinks... but even if that were true, it changes nothing. Nature is taking out less than it would if not for pollution. Ok... but the accumulating excess is STILL entirely derived from human emissions since even these 'reduced' natural sinks are greater than the natural emissions.
  4. Bugai, Your own model suggests that T cannot possibly be 5-10 years. Say we linearize about the pre-industrial level and assume that's the equilibrium. The resulting DE will be dC/dt=E_a-C/T Notice that E_n disappears due to linearization. C here is the CO2 above the preindustrial level of 280ppm. Currently we have dC/dt=14 Gt/yr, E_a=29 Gt/yr gives C/T=15 Gt/yr Now the CO2 level has increased by about 100ppm, with is about 770Gt. This yields T of 51 years.
  5. bugai#195: "we destroy the CO2 sink by pollution of the oceans" We pollute the oceans, sufficient to 'destroy' the CO2 sink, yet we do not produce the CO2 that goes into the atmosphere? BTW, we also influence atmospheric ozone and produce CO, N2O, NO, among other gases, but not CO2? Seems like an inconsistent position to me.
  6. Bugai #201, Also in the Joos et al. paper you cited, they've set the air-sea exchange to zero for figure 3 (see appendix A1). The curves in their figure shows how quickly tracers move from the surface to deep ocean, and that is certainly not the relaxation time we're discussing.
  7. "So without our contribution to atmospheric CO2, CO2 levels would be declining by >2ppm/year right now". This cannot be right. The amount of update of CO2 by natural sinks must have some dependence on pCO2. If natural sinks reduce CO2 by 2ppm/ year we would have been ice age long ago.
  8. Bugai, You position is untenable, because you must solve three intractable problems to support it. First, humans have burned hundreds of gigatons of carbon that have been sequestered underground for hundreds of millions of years. 1) If this carbon has not gone into the atmosphere and oceans, then where has it all gone? Second, there must be a source of carbon which has both raised atmospheric levels by 100 ppm, and introduced an equivalent amount of CO2 into the oceans (and very noticeably lowering pH there). 2) What is the source of the hundreds of gigatons of carbon that have gone into the atmosphere and the oceans? At the same time, if you do propose another source of carbon, and another destination for anthropogenic carbon, there must be some mechanism which somehow preferentially puts anthropogenic carbon in one place (if you can find it) while adding only your other source of carbon (if you can find one) to the atmosphere and ocean, in a fashion which makes the existence and quantity of anthropogenic carbon meaningless in affecting the balance. 3) What mechanism can possibly exist that "knows" how to intelligently separate anthropogenic from natural carbon, adding the former only to some undefined (and presumably bottomless) sink, while putting the latter into the atmosphere and oceans. No matter what other things you want to argue, the bottom line is that there is a pool of carbon in the system, an additional pool of carbon (fossil fuels) that had been separated from the system but have now reintroduced in a very short time frame, and there are only limited and measurable places for that carbon to go in similarly short time frames (those places being the atmosphere, the oceans, and biomass). No matter what you come up with, anthropogenic carbon must go somewhere, and in so doing, it must be affecting the balance. No matter what you come up with, anthropogenic carbon must be contributing substantially (actually, solely) to the CO2 levels in the atmosphere and oceans. There is no way out of this inconvenient truth.
  9. scaddenp - Well, we're currently emitting enough CO2 to raise atmospheric concentrations at >4ppm/year. It's actually rising at ~2ppm/year, hence natural sinks are (currently) absorbing ~2ppm. So, if we were to suddenly stop emitting CO2, the natural sinks would initially absorb 2ppm/year, with an expected decrease over time (multiple decaying exponentials due to the various pathways), as the imbalance decreases. See my post and the IPCC links here, and also here for the curves. It's definitely rate(s) dependent on the pCO2 imbalance.
  10. bugai wrote: "And yes, I claim it is the problems with a too weak sink of CO2, not with extra emission." However, the data show that the natural sinks are stronger than the natural sources and have been steadily strengthening relative to sources for at least the last fifty years. SO the idea that the sinks are too weak doesn't survive first contact with the data, they are only weak in the sense that they can only cope with half our emissions on top of all natural emissions. Which suggests that CO2 levels have only been rising because of anthropogenic emissions. Bugai is making an error that many have made before (confusing residence time with relaxation time). Making a mistake that others have made before is nothing to be embarassed about - we all make mistakes. Not being able to accept you have made a mistake on the other hand is another matter. For that reason it is always a good idea to assume you are wrong and take counter-arguments seriously.
  11. re: Sphaerica @208 You've left the loophole that the unknown sink that surely must exist (by denier argument) is only taking most of the anthropogenic CO2, not all of it. Thus, the unknown natural source is also affected by this same sink, so point 3) is avoided. To close this loophole we can look at quantities. Current thought is that half the anthropogenic CO2 is removed from the atmosphere. Let's assume that the proportion is larger: - if 3/4 is removed, then 3/4 of the unknown natural source is also removed, and this means that the unknown natural source is of the same size as the anthropogenic source. Corollary: half the rise is anthropogenic. - if 80% is removed, then 80% of the unknown natural source is also removed, and this means that the unknown natural source has to be 1.5X larger than the anthropogenic source. Corollary: 40% of the rise is anthropogenic. - if 90% is removed, then 90% of the unknown natural source is also removed, and this means that the unknown natural source has to be 4X larger than the anthropogenic source. Corollary: 20% of the rise is anthropogenic. - if 95% is removed, then 95% of the unknown natural source is also removed, and this means that the unknown natural source has to be 9X larger than the anthropogenic source. Corollary: 10% of the rise is anthropogenic. - if 99% is removed, then 99% of the unknown natural source is also removed, and this means that the unknown natural source has to be 49X larger than the anthropogenic source. Corollary: 2% of the rise is anthropogenic. To get to a point where most of the rise is not anthropogenic in origin, and (to keep consistency) there is an unknown natural source that plays by the same rules as the anthropogenic one, you have to posit a huge, undiscovered natural source that nobody has noticed. As they say, that dog won't hunt.
  12. 211, Bob, I'm not sure I understand. If you have some sort of sink that takes most of the anthro CO2, then it also has to take most of the natural CO2 as well. But if the rise in CO2 is primarily from this unknown natural source, then for that natural sink to be taking most of the anthro CO2, it has to also take proportionally more (i.e. most of) the natural CO2. That means that in order to have raised atmospheric CO2 levels by 100 ppm while overwhelming this mysterious natural sink that has sucked "most" of the anthro CO2 out of the air, then that mysterious natural CO2 source must be absolutely huge! A whole order of magnitude greater than the hundreds of gigatons of CO2 we've generated by burning fossil fuels. What the heck is that source? [My own conjecture is that an alien race is burning their own fossil fuels, but using special teleportation technology to deposit their CO2 in our atmosphere.]
  13. Sphaerica#212: "If you have some sort of sink that takes most of the anthro CO2" Problem solved. A new natural sink is emerging before our very eyes. A place where the low salinity surface waters ... are undersaturated with respect to CO2 in the atmosphere and the region has the potential to take up atmospheric CO2, although presently suppressed. This marvelous new sink for CO2 has tripled over the last 3 decades. Just what the doctor ordered!
  14. Sphaerica@212. Exactly. You appear to understand perfectly. The numbers I calculated were based on the assumption that the extra sucking applies only to anthropogenic CO2 and the new magical natural source that looks just like anthropogenic CO2 (i.e., same isotopic signature, etc.). The numbers I present say that if this removal ratio is 99%, then this mysterious natural source is 49x larger than the anthropogenic one - i.e., the 30 Gt anthropogenic source is running in parallel with a natural source of 1470 Gt. Kind of hard to miss in the grand scheme of things, since we seem to be able to identify the long-existing natural sources of much smaller quantity than this. This new source also seems to be rising at the same rate as anthropogenic CO2. Another astounding coincidence. ...but at least you have a conjecture as to the source. Unlike the "skeptics". And as muon points out, the same logical applies to any new sink we haven't noticed - it is "emerging before our very eyes". It has some magical property that allows it to turn on and grow at just the right rate. ...but muon's hypothesis seems a bit far-fetched. I think it is more likely that Sphaerica's alien race has introduced a cap-and-trade scheme, and some enterprising alien has realized that they can make oodles of money by scarfing CO2 out of our atmosphere and get credit for sequestering it. Unfortunately, the same conspiracy that made up the AGW hoax is also hiding the fact that we've made contact with these aliens, and have one of their teleportation devices stored at Area 51. We're not allowed to use it to solve our problem. [Yes, I know that it is inconsistent to have the same conspiracy both make up the problem and hide a real solution to the same problem. In the People's Republic of Made-up-istan, consistency is not a legal obligation.]
  15. This is a dramatic oversimplification of factors affecting carbon dioxide levels. Relatively small percentage variations in natural "absorption" rates can overshadow all human fossil fuel output in either a positive or negative direction. To say "However, natural CO2 emissions (from the ocean and vegetation) are balanced by natural absorptions (again by the ocean and vegetation)" is simply a statement without proof. Such conclusions totally ignore the impact on the level of photosynthesis which is in turn affected by the quality of plant life, that in turn being affected by the level of carbon dioxide. Removing the natural carbon sink found in forests, for example, has been shown to have about four times the effect on carbon dioxide levels than that of fossil fuel emissions.
    Response:

    [DB] Link to off-topic website snipped.  Please endeavor to stay on-topic to the subject matter of the thread on which you are placing comments.

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  16. Was not sure where else to post this. The (evil/job destroying) EPA has a GHG Data Page. Pretty nifty. If this has made an appearance on SkS before I have missed it.
  17. pbjamm... WOW! I was trying to find a link to Norville Barnes in the Hudsucker Proxy saying "WOW!" but alas...
  18. To say that the levels of CO2 before the Industrial Revolution remained static is just wrong. CO2, temperatures and water levels have fluctuated quite dramatically for a long time. To have a serious debate, we must start with known facts - not a bunch of hypotheses inferred from data. We all know that data can be used to support any bias. There is simply no evidence that shows absolutely that carbon dioxide levels are the root cause of the phenomenon known as "global warming." It is a fact that there is a "greenhouse effect" taking place, but is higher carbon dioxide levels the root cause or just a symptom? A simple look at the data could also suggest that long cycle changes in ocean currents or a cooling/shrinking planet or some other factor could just as easily be the culprit - and, of course, it could also be mankind. There is no evidence that proves that shutting off all man-made sources of carbon output - even if it were possible - would alter the changes taking place. There is an abundant supply of common sense that says shutting off all carbon generating activities by mankind would cause a great deal of hardship to a lot of people! Wouldn't our energy be better spent trying to find ways to live on a warmer planet? Why do we assume - with some arrogance - that mankind has all this power to affect global temperature? Why do we assume that mankind is some non-natural force? Isn't mankind just another part of nature? Like so many dialogues in our society today - this one is taken over by biased people trying to shout over one another, rather than starting with facts and ending with a course of action.
    Response: [Sph] Other mods, please do not delete this comment for being off-topic. Please leave it as a testament to how much passion, intensity and surety a person can put into a position as long as it is based on assumption and hearsay rather then investigation, education, and understanding.
  19. 218, primespot,
    A simple look at the data...
    An overly simplistic look at anything will lead you to wrong conclusions. Your "look at the data" is so far off the mark it suggests that you haven't looked at the data at all, you've listened to others, or presumed that the data says what you'd like. An intelligent and informed look at the data will show you that your statements are false.
    ...shutting off all carbon generating activities...
    No one is saying this except for fear-mongers who want to scare other people out of thinking things through. What is necessary is aggressive but moderate action now, rather than complete lethargy and inaction. Failure to act now will simply require more desperate measures later, measures that will hurt society and economies, because they'll have to be too radical and too aggressive.
    ...find ways to live on a warmer planet?
    No, because it will be more expensive to do so, and the planet will not simply "be warmer." That's a gross misunderstanding of what we're facing.
    Why do we assume that...
    It's not an assumption, it's an understanding based on knowledge and facts.
    Like so many dialogues in our society today - this one is taken over by biased people trying to shout over one another, rather than starting with facts and ending with a course of action.
    And finally, in conclusion, you say something sensible. Now that you have all of that shouting and lathered up umbrage out of your system, welcome to Skeptical Science! This site has a wealth of information which will help to educate you on the issues so that you can understand them, rather than shout platitudes based on ignorance and a complete misunderstanding. Please use the search box in the upper left hand corner. Many articles are presented in beginner, intermediate and expert versions, whichever best suits your own personal starting point and level of understanding. When you have learned more, and are able to actually make supportable statements, then we can talk. Until then, standing up and shouting as loudly as you can that you are right and everyone else is crazy will not be nearly as effective as first learning and then starting with facts and ending with a course of action.
  20. primespot: -We have samples of the air going back 800,000 years in ice cores that show the concentrations of CO2. These are "known facts". -Recent carbon dioxide increases have been caused by combustion of fossil fuels, even some of the skeptics like Willis Eschenbach and Roy Spencer accept that without reservation. This isn't a disputed hypothesis, this is as close to accepted fact as we get in science. -What evidence is there that a "shrinking planet" could have contributed to the rise in CO2? Surely, you are not serious. -Skipping over some of your other assertions, why do you believe that it is "arrogance" to assume that mankind can influence the climate? Do you think, for example, that it is arrogance to think that a nuclear war would be catastrophic? I suppose that your logic would at least lead you to believe that a nuclear war would be an entirely natural phenomenon. -I agree with you that this dialogue "is taken over by biased people trying to shout over one another, rather than starting with facts and ending with a course of action". But not in the way you think. -It's perhaps arrogance on your part to think that your "common sense" arguments are sufficient to overcome the consensus opinions of experts who have spent their lives studying this problem.
  21. To say that the levels of CO2 before the Industrial Revolution remained static is just wrong.
    Straw man. No scientist is saying that. What they are saying, however, is that the concentration of atmospheric CO2 is increasing in proportion to the (~10) billions of tons of carbon that humans burn annually, and that this rate of increase is significantly greater than it has been for hundreds of thousands - if not millions - of years. Given that a little less than half of annual human emissions are sequestered, what do you think that this continually-increasing extra greenhouse gas is doing to the planet's climate?
    CO2, temperatures and water levels have fluctuated quite dramatically for a long time.
    What you mean is that "CO2, temperatures and water levels have fluctuated quite dramatically on occasions far back over geological time"... And every time that they fluctuated dramatically, there was a concurrent dramatic impact on the biosphere. And something that seems to completely escape the Denialati is that the biosphere is what keeps humanity alive. If anyone doesn't believe this I am (and I'm sure others would be) quite happy to dissect this concept in fine detail... We are absolutely and inextricably beholden to the primary productivity of solar-driven photosynthesis (and its direct products) for our survival. Hurt the biosphere, and humanity is hurt. With the passing of abundant fossil energy this dependency will only become more - and permanently - stark.
    To have a serious debate, we must start with known facts - not a bunch of hypotheses inferred from data.
    Consensus climatology and ecology absolutely do start with "known facts". You seem to be either oblivious to, or entirely ignoring, them.
    We all know that data can be used to support any bias.
    "[D]ata can be used to support any bias" only if one does not use the data correctly. If you adhere to your statment then it is only a reflection on how you and your associates are wont to "use data".
    There is simply no evidence that shows absolutely that carbon dioxide levels are the root cause of the phenomenon known as "global warming."
    The only absolute in science is that there are no absolutes. If your presumption of irrefutable absoluteness is replaced with something such as "strong certainty", then your statement is completely refuted.
    It is a fact that there is a "greenhouse effect" taking place, but is higher carbon dioxide levels the root cause or just a symptom?
    To the extent that there are no absolutes, as noted above, it is still defensibly - strongly defensibly - possible to ascribe most (if not all) contemporary global warming to human CO2 emissions.
    A simple look at the data could also suggest that long cycle changes in ocean currents or a cooling/shrinking planet or some other factor could just as easily be the culprit...
    No.
    ...and, of course, it could also be mankind.
    "Could" in the same way that falling from 2 000 metres without a parachute "could" kill you.
    There is no evidence that proves that shutting off all man-made sources of carbon output - even if it were possible - would alter the changes taking place.
    Eh? Were's your evidence for that?
    There is an abundant supply of common sense that says shutting off all carbon generating activities by mankind would cause a great deal of hardship to a lot of people!
    "Common sense" is not science, and is not even a reliable guide for objective correctness. This is a basic tenet of high school level scientific philosophy.
    Wouldn't our energy be better spent trying to find ways to live on a warmer planet?
    No. If you don't understand why, try teaching a mountain pygmy possum to live without winter snow, or a penguin to live on a tropical beach, or walrus and polar bears to live without sea ice. The same issues apply to humans, if in slightly more subtle and complex (but no less important) ways.
    Why do we assume - with some arrogance - that mankind has all this power to affect global temperature?
    Why not?
    Why do we assume that mankind is some non-natural force?
    Simply, because human intelligence is an emergent phenomenon of a type and magnitude that has not previously had expression in the history of the planet.
    Isn't mankind just another part of nature?
    To the extent that human intelligence distinguishes our species from the rest of the planet - the answer is an emphatic "no".
    Like so many dialogues in our society today - this one is taken over by biased people trying to shout over one another, rather than starting with facts and ending with a course of action.
    This is the only accurate thing that you've said. Unfortunagely for you, the "biased people" are those who have the temerity, if not the objective evidence or even the intellectual capacity, to contradict parsimonious science. In other words, your crowd...
  22. primespot wrote: "To say that the levels of CO2 before the Industrial Revolution remained static is just wrong. CO2, temperatures and water levels have fluctuated quite dramatically for a long time. To have a serious debate, we must start with known facts - not a bunch of hypotheses inferred from data." I completely agree. In which case you ought to start by presenting the evidence that says there were substantial fluctuations in CO2 prior to the industrial revolution, since say the end of the last major glaciations (of course glaciations have a large effect on CO2 levels, but this doesn't explain recent changes). Another line of evidence that might support your position would be evidence that CO2 levels had been higher than present over the last 800,000 years or so. Starting with facts would be great, but it is exactly the thing you did not do. Present your evidence piece by piece and we will happily engage in a scientific dialogue with you. Note I say "piece by piece" because scientific discussion requires depth as well as breadth; so building an argument gradually assessing each pice in turn and progressing onto the next step when agreement is reach has been found to be thebest way to make progress.
  23. It's very odd of primespot to castigate this thread with: To have a serious debate, we must start with known facts - not a bunch of hypotheses inferred from data and Like so many dialogues in our society today - this one is taken over by biased people trying to shout over one another, rather than starting with facts and ending with a course of action. I find it unusual, because data (results derived from empirical observation or from calculations based on observation) are to me synonymous with facts, and you don't infer hypotheses from data - you infer conclusions and then postulate hypotheses. In addition as others have stated upthread, serious scientists and their organizations and synthesis reports (such as the IPCC) do, in fact, draw their conclusions (AGW is real and action to prevent it where possible is required) from known, easily-verifiable facts. It's not out of line to say that there is a rather natural chain of inference such that: 1 - basic physics predicts humans can alter the global climate for the worse 2 - empirical observation shows that humans are altering the global climate, for the worse - and at a rate nearly unprecedented in geological history 3 - the costs and drawbacks to simply allowing this process to go on unchecked and trying to adapt to the resulting changes can be shown to be much greater than the costs and drawbacks to mitigating its effects and preventing its growth 4 - as such, there is a clear imperative for action, in the form of reducing human emissions of known heat-trapping gases Since this position, as far as I can tell, is essentially what the IPCC, prominent climate scientists, large bodies of science (the National Academies, Royal Society, & such) and of course Skeptical Science are espousing, once again I must emphasize primespot's attempt to castigate SkS on this thread on this account mystifying.
  24. "we must start with known facts - not a bunch of hypotheses inferred from data" One should never allow one's argument to become contaminated with facts (or data for that matter). -- image linked to source page 800 years of minimal fluctuations in atmospheric CO2 (at what might be called a 'pre-industrial level'), followed by an abrupt upswing. Why would anyone base a hypothesis on that?
  25. Posted by wsugaimd here, and moved because of topic:
    "Thanks for the info. Sorry for posting on a wrong? link. First time here so I'll learn...I'm coming from a biology background and I'm not sure of the argument that its the C02 driving the temp. Heres why... Its estimated that there are 560 billion tons of biomass, not including bacteria or oceanic bacteriophage/viruses which far out weigh all prokaryotic and eukaryotic life forms. There are 10 million viruses in a drop of seawater. What I'm trying to say is that as temp rises, life forms increase metabolism, i.e., release more C02. Even plants exhale C02 at night. And I believe the C02 exhaled by all biomass on earth has far more impact than the few "pennies" our cars put out. Is my CO2 different from a frogs? I think not."

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